TSgt Abernathy maintained her stance outside the door to the former server room, occasionally stealing a glance at the rest of her team as they made their way back to the stairwell. There was no sign of anything trying to come through the door after them. Either the spiders had a very short-term memory, or they stopped caring about them once they had escaped the room.

She wished there were a way to figure out just what they were up to.

“Abernathy to Raskin,” she radioed. “Requesting permission to stay behind and dig up some more intel. Over.”

Thirty minutes, thought TSgt Abernathy. It wasn’t a lot of time. But it was something.

“Sir, with any luck this is our last chance to learn about this thing. We can’t pass up an opportunity like this. Over.”

“Sergeant, you heard the order. Over.”

“Sir, please,” TSgt Abernathy replied. Unlike Maj Raskin, TSgt Abernathy had volunteered for a tour in AFEXOCOM. Ever since she was a little girl, she had stared up at the night sky and wondered if we were alone in the universe. AFEXOCOM gave her a fleeting chance to find out, or at least an opportunity to try. And now that she was here, in the middle of it, living her dream better than she had really thought possible, she didn’t want to have to let it go. “Over.”

The radio answered with the soft static of an unused channel. TSgt Abernathy let out a quick sigh and started sidling towards the stairwell, not turning her back to the door.

TSgt Abernathy pocketed the radio. Twenty-nine minutes. One mile between the building and the fallback perimeter. Assuming there weren’t going to be any vehicles available, that would be eight minutes, maybe nine, to cover the distance. Factor in another two to get out of the building itself. Buffer another five for a contingency. That left thirteen minutes to work with. She checked her watch.

She could work with thirteen minutes.

She quickened her pace and climbed up a flight of stairs, exiting on the basement level. She paused briefly when a burst of static came through the radio, but when nothing followed, she continued on her way to the lab. Might as well get straight to the heart of the matter. She pressed her ear to the door, straining to hear the telltale sound of metal on floor tile on the other side.

Nothing.

She opened the door and slid inside. The emergency lighting didn’t illuminate much, but it did well enough to show the lab was unchanged from the last time she had seen it. She crept over to the door to the anechoic chamber. Also silent. She opened the door.

The Mackinelly Device was still resting on the floor in the center of the room. She found herself a little disappointed. She had expecting the room to be crawling with the spiders as well. This was their home base, wasn’t it? Or was it just a ship that brought them here, discarded once it was no longer needed?

“Abernathy to Raskin,” she radioed. “I’m at the Device. No change in status. Over.”

The radio responded by blaring with static.

“Abernathy to Raskin. Major, do you read, over?”

More static.

What was going on out there, she wondered. She checked her watch. Six minutes before she had to start moving, but there was still time.

More bursts of static. Why the sudden interference? There hadn’t been any until Roberts was attacked. Was she being jammed? Was the Device trying to cut her off? She glanced at the door. Still no spiders. The path out was still clear, at least until the hallway outside.

As she edged towards the exit, there was a spark of pattern recognition in the back of her mind. The static didn’t sound like she expected from a jamming signal. Jamming would be constant. A roar drowning out everything else as the radio’s frequencies were flooded with energy. This was different. Bursty. Discrete bursts.

She listened more attentively. Burst. Silence. Two quick bursts. Silence. Now three. Then four. Then five. A longer silence. Then one again, followed by two.

It wasn’t jamming. It was counting.

She remembered one of the strategy planning sessions she and Maj Raskin would have back on base, long before the Mackinelly Device had appeared. One of the scenarios they considered was: flying saucer lands, and aliens step out; how do you talk to them? You don’t have any common language, no common culture, no common experience. What do you say to them where they will both realize you’re trying to communicate with them, and they’ll be able to understand it?

Elementary math. Neither could imagine how you could achieve interstellar travel without being able to count. Nor could they find any natural source that emitted integers. So: figure out a frequency they can hear, and start tapping out small numbers.

Now TSgt Abernathy found herself on the flip side of the scenario. The Mackinelly Device had noticed the radio frequencies, and was using them to count to five. Over and over. No doubt waiting for her to notice.

She waited for the next set of five pulses of radio static. Once they finished, she pressed and released the transmit button of her radio six times, slowly enough to hopefully be unmistakable. She waited.

There was relative radio silence for a few seconds, and then seven pulses of static. She replied with eight. Nine came back.

They were communicating. Only enough to signal to each other that they were capable of communicating, but that’s how you start. Given time, the plan she and Maj Raskin had devised involved transitioning from a unary to binary encoding of numbers, then introducing symbols for operators like plus and equals, then build up to passing equations back and forth to each other. Maybe by the time you say Euler’s formula and it replies with Fermat’s Last Theorem, you can start working on a way to encode “Hello.”

“Sorry,” she said to the device, not that it was going to be capable of understanding her, and bolted for the door. She was out of time. Less than that, really. As she bounded up the stairs two at a time, she wondered just how quickly she could run a mile. Then she realized that “one-mile radius” didn’t account for any twistiness in the roads leading out of there.

As the launched herself through the front doors of the building, she started to lift up the radio to alert Maj Raskin of what she had just discovered, but then realized it would be futile. Intentionally or not, the Mackinelly Device was jamming communications by hijacking the frequencies. Besides, she was going to need everything in her lungs to propel her past the presumed blast radius of whatever was on its way.

All thoughts about the Mackinelly Device and first contact and robot spiders and whatever was being built in the subbasement left her mind as every cell in her body dedicated itself to getting her out of there. Her feet barely touched the ground, for fear of lingering too long on the pavement and getting left behind by the rest of her body. If she made it back alive, the part of her brain not busy pumping her legs swore never to use the phrase “run for your life” casually again.

She finally collapsed against the far side of a National Guard transport marking the perimeter, gasping for air. A shadow blocked out the sunlight as someone stepped up to her.

“Good of you to join us, Sergeant,” Maj Raskin said.

“Sir,” she managed to wheeze out between breaths.

“Relax, Sergeant, you made it. With plenty of time to spare, no less.”

“Sir?”

“There’s about four minutes before the action starts.”

Right, she thought. The five minutes’ contingency buffer. It worked best if you forgot about it as soon as you factored it in, after all.

“And Sergeant?” Maj Raskin said.

“Sir?”

“After that, you don’t have any excuse for not signing up for the next 5K Fun Run anymore.”

“Sir.” She then jolted as she remembered what had happened ten minutes ago. “Sir! You have to call off the countdown!”

“Sergeant?”

“The Mackinelly Device! It’s intelligent!”

“What do you mean?”

“Unary sequence introduction protocol! That’s what the jamming was! It was trying to communicate!”

Maj Raskin frowned. “Too late for it now. One minute.”

“But sir!” TSgt Abernathy protested.

“Besides,” Maj Raskin continued, “if anything that makes it worse. An intelligent alien device taking over the building and attacking my men? My hands are tied even if there was time to call the strike off.”

“Right! How’s Roberts, sir?”

“He’s doing fine so far, fortunately. You did the right thing in there with him.”

“Thank you, sir.”

Maj Raskin checked his watch. “It’s about time.”

TSgt Abernathy picked herself up and turned back towards the building, its roof barely visible above the tree line. She couldn’t hear anything above the commotion of the crowd behind her. She looked up. The airspace was empty. She had expected to see bombers approaching by now.

The air exploded.

There was a blinding flash above the building, replacing her view with searing white light. TSgt Abernathy covered her eyes and ducked behind the vehicle. Training triggered instinct as she opened her mouth and covered her ears just before the shock wave reached the perimeter. The sound left her ears ringing, and for a few seconds it felt like the temperature had doubled. When she dared look again, she saw clouds of thick black smoke rising from where the building had been. In front of the smoke, flames leaped up from the tops of the trees, having been ignited by the heat from so close. Sirens blared as nearby fire trucks sprang to life and started down the road in response.

“What was that?” TSgt Abernathy wondered aloud. “For a second there I thought it was a nuke.”

“I’m not sure myself,” Maj Raskin replied. “SECDEF only referred to it as ‘Mojo’.”